SPATIAL AND TEMPORAL VARIATION IN PHOSPHORUS BUDGETS FOR 24

WATERSHEDS IN THE LAKE ERIE AND LAKE MICHIGAN BASINS

PRESENTED BY:ARIF REZA

ENVIRONMENT ECOLOGY LAB

INTRODUCTION

•Eutrophication of the Great Lakes, attracted

great public attention in the 1970s.

•The 1972 Clean Water Act brought about

reductions in point source loadings of P.

•Periodic hypoxia in the hypolimnion of the

central basin of Lake Erie has reemerged.

INTRODUCTION

•Attention has re-focused on P loading and cycling within the

Great Lakes basin.

•Net anthropogenic phosphorus inputs (NAPI) have been

found to correlate strongly with land use, agricultural inputs,

and human population density (Boyer et al. 2002; Russell et

al. 2008).

• Net nutrient inputs and their relationship to river export has been

useful -

• For identification of primary nutrient sources (Boyer et al. 2002)

• To predict present or future river export (Han et al. 2009; Howarth

et al. 2006)

• An overall measure of anthropogenic nutrient loading (Howarth et

al. 1996; Russell et al. 2008).

INTRODUCTION

OBJECTIVES

• Evaluate the relationship between NAPI and riverine TP

export to determine whether NAPI can be used to predict

riverine P export, and how the relationship might vary with

regional conditions.

STUDY AREA

Fig. 1 Locations and areas of the 18 Lake Michigan watersheds and 6 Lake Erie watersheds

Selection Basis: • Availability of river water quality data• Watershed land use• Geological and climatic characteristics • Agricultural management practices

(Table 1). • The 18 LM watersheds comprise 74%

of the entire LM basin, and the 6 LE watersheds cover 37% of the entire LE basin.

STUDY AREA

Basin ID Watershed StateUSGS

gauging station

Area(km2) Major surficial deposits (%)

Pop. Density

Land use (%)

Agr For Urb

Lake Michigan 1 Root WI 04087240 510 C(100) 565 76.7 3.1 19.0  2 Milwaukee WI 04087000 1,818 L(68) 117 73.9 7.9 12.2  3 Sheboygan WI 04086000 1,106 L(54), C(38) 69 82.0 7.2 2.5  4 Fox WI 04084500 15,825 L(37), C(32), SG(27) 32 51.1 27.2 2.4  5 Oconto WI 04071000 2,543 L(46), SG(36) 10 27.5 52.1 0.7  6 Peshtigo WI 04069500 2,797 L(48), SG(51) 9 20.7 54.7 0.9  7 Menominee WI, MI 04066003 10,541 L(68), SG(31) 7 7.1 73.1 0.7  8 Ford MI 04059500 1,165 L(90) 3 7.1 53.5 0.2  9 Escanaba MI 04059000 2,253 L(67), SG(20) 7 5.4 66.7 1.1  10 Manistique MI 04056500 883 SG(62), P(19) 3 5.0 49.5 0.3  11 Manistee MI 04126000 4,343 SG(65), L(35) 8 18.3 73.1 1.0

  12 Pere-Marquette MI 04122500 1,764 SG(55), L(42) 9 17.6 71.2 0.7

  13 Muskegon MI 04122000 6,941 SG(51), L(36) 18 33.6 47.7 2.8  14 Grand MI 04119000 14,292 L(64), SG(26) 85 75.4 13.9 5.5  15 Kalamazoo MI 04108500 5,164 L(50), SG(48) 84 75.1 12.6 6.1  16 St. Joseph MI, IN 04101500 12,095 L(59), SG(29) 67 80.4 9.3 5.5  17 Trail Creek IN 04095300 153 SG(48), C(40) 237 50.0 27.7 18.0  18 Burns Ditch IN 04093500 857 C(88) 284 63.7 13.3 21.7

Lake Michigan basin: area-weighted average L(46), SG(39), C(12) 50 48.7 34.5 3.6Lake Erie 19 Huron MI 04174500 2,343 SG(49), L(41) 222 49.1 27.8 8.9

  20 Raisin MI,OH 04176500 2,740 C(58), SG(28) 59 79.4 14.1 1.8  21 Maumee IN, OH 04193500 16,376 C(84) 50 87.8 7.5 2.6  22 Sandusky OH 04198000 3,217 C(89) 37 88.3 9.3 1.3  23 Cuyahoga OH 04208000 1,823 C(35), SG(27), L(23) 360 31.0 41.6 17.3  24 Grand OH 04212100 1,825 C(94) 62 38.8 44.2 2.0

Lake Erie Basin: area-weighted average C(74), SG(11), L(11) 96 77.0 14.6 3.8

Table 1 General characteristics of the 18 Lake Michigan and 6 Lake Erie watersheds

LAND USE

37%

27%

14%

22%

Land use of LM watersheds

Corn

Alfalfa

Soybean

Others

Source: USBC 1977, 1980, 1983, 1989, 1995; CTIC 2009

PHOSPHORUS BUDGETS•Net Anthropogenic Phosphorus Inputs (NAPI)

•Estimated at the watershed scale, considering only

newly transported P from outside sources, and

excluding internally recycled components.

•NAPI estimates the difference between

anthropogenic inputs and.

PHOSPHORUS BUDGETS

Fig. 2 Conceptual diagram for phosphorus budget including inputs, system, and outputs

RIVERINE TP CONCENTRATION AND FLUXES

• For the 18 LM and 6 LE watersheds annual river TP export

loads estimated for the five census years from 1974 to 1992

based on approximately monthly TP concentrations (USEPA

2007) and daily discharges (USGS 2008) using the USGS

Estimator Regression Model (Cohn et al. 1989; Richards 1998).

RESULTS : PHOSPHORUS BUDGETS

Key Watershed name Atmos. Dep. Fert. Net import

in foodNet import in

feed Detergents NAPI Manure Crop export

1 Root 6 648 254 -137 415 1186 194 4592 Milwaukee 6 793 -78 120 92 934 558 6053 Sheboygan 6 1130 -189 146 62 1156 678 7084 Fox 6 574 -119 62 25 548 391 4495 Oconto 6 277 -72 62 8 280 236 2256 Peshtigo 6 136 -25 33 6 155 97 887 Menominee 6 42 -7 14 6 61 39 368 Ford 6 88 -4 20 8 117 42 369 Escanaba 6 10 6 6 9 36 9 7

10 Manistique 6 14 1 6 2 28 8 711 Manistee 6 85 -4 23 9 119 44 4112 Pere-Marquette 6 329 -14 49 10 380 88 9613 Muskegon 6 184 -29 56 9 226 125 12214 Grand (MI) 6 786 -41 42 55 848 234 42515 Kalamazoo 6 704 -36 93 45 812 200 39116 St. Joseph 6 1068 -68 15 35 1056 243 66217 Trail Creek 6 1323 -30 -465 35 869 165 80218 Burns Ditch 6 1626 89 -426 142 1438 87 637

Avg. area-weighted (LM) 6 501 -50 38 31 558 204 31419 Huron 14 548 128 -46 182 826 121 26920 Raisin 14 1203 -42 -262 45 959 160 62321 Maumee 14 1460 -90 -315 43 1112 154 87522 Sandusky 14 1858 -89 -533 42 1291 116 90823 Cuyahoga 15 244 194 25 648 1125 94 12424 Grand (OH) 15 336 13 85 117 566 176 154

Avg. area-weighted (LE) 6 1310 -42 -265 99 1112 145 710

Manure and crop export fluxes are included here for reference but are not included in budgets. All units in kg-P km-2 yr-1

Table 2: Complete NAPI budgets for each watershed averaged across 5 agricultural census years (1974, 1978, 1982, 1987, 1992)

RESULTS : PHOSPHORUS BUDGETS

Fig. 3 Phosphorus inputs to the 24 LM and LE watersheds are strongly related to land use, showing a

positive relationship with land in agriculture (a), a positive relationship with land in agriculture and

urban use combined (b), and a negative relationship with forested land (c)

RIVERINE TP EXPORTS AND RELATING NAPI TO RIVER EXPORT (SPATIAL)

Fig. 4 Relationship between NAPI and river total phosphorus (TP) export for Lake Michigan (a) and Lake

Erie (b) watersheds across the 5 agricultural census years

RELATING NAPI TO RIVER EXPORT (SPATIAL)

•In 18 LM watersheds riverine TP exports varied

significantly by census year, ranging from 3.6 -

5.4%.

• In 6 LE watersheds exported a greater fraction

of their P inputs over time, ranging from 5.6 -

25.3%.

RELATING NAPI TO RIVER EXPORT (SPATIAL)

Fig. 5 Regression relationship between river total phosphorus export and NAPI for individual watersheds of the Lake

Erie, Lake Michigan, and Chesapeake Bay basins.

TEMPORAL RELATIONSHIP BETWEEN NAPI AND RIVER EXPORT

Fig 6. Scatter plots showing the temporal relationship between NAPI and annual TP exports over five different

census years (1974, 1978, 1982, 1987, and 1992)

CONCLUSION

• Fertilizer was the dominant input, but detergent was the largest input in the most urbanized watershed. • NAPI increased in relation to area of disturbed land (R2 = 0.90) and

decreased with forested and wetland area (R2 = 0.90). • Export of P by rivers varied with NAPI, especially for the 18

watersheds of LM (R2 = 0.93), whereas the relationship was more variable among the six LE watersheds (R2 = 0.59).• On average, rivers of the LE watersheds exported about 10% of NAPI,

whereas LM watersheds exported 5% of estimated NAPI.

FORESTED AREAS

AGRICULTURALLY DOMINATED AREAS

CONCENTRATED URBAN AREAS˂ ˂

THANK YOU